All studied biomes
8. What is snowline? A snow line is the point above which snow and ice cover the ground throughout the year.
The actual snow line may seasonally be significantly lower.
9. What is treeline (timberline)? The treeline is the zone where conditions become too harsh to support growth
as large as trees. When viewing a mountain from the side, this line is visible as the place where forests stop and
snow, ice and rock begin. Sometimes there is a transition called the krumholtz line, where trees become stunted
and warped before disappearing entirely as the altitude increases.
10. Name traditional human activities in tundra and polar desert areas.
Polar desert: Few direct threats exist for this ecoregion, simply because humans are largely absent. But where
humans have tread, this ecoregion has suffered. Plans for a northern shipping route through the Russian Arctic
could open up oil, gas, and other natural resources for exploitation
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